In this case looks like it has just been rounded up to full 256KB. There's really no reason for that and the more correct value would be the exact 261120. Sending that extra 1024 bytes shouldn't be an issue in most cases though.

In this case looks like it has just been rounded up to full 256KB. There's really no reason for that and the more correct value would be the exact 261120. Sending that extra 1024 bytes shouldn't be an issue in most cases though.

Actually Curtis is correct. Sending over the incorrect size can result in an error in the USB bulk write. Before seeing this post I was using 262144 and I would sporadically get:

Code:

bulk_write error. -14USB error: error submitting URB: Bad address

It would also not draw the last 10 or so lines on the LCD. After I set it to the correct size I no longer get this error.